RE: [RFC V4 1/3] add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
> From: Joe Perches [mailto:j...@perches.com] > > We also change byte_rev_table[] to be static, to make sure no drivers > > can access it directly. > > You break the build with this patch. > > You can't do this until the users of the table are converted. > > So far, they are not. > > I submitted patches for these uses, but those patches are not yet applied. > > Please make sure the dependencies for your patches are explicitly stated. > Oh, byte_rev_table[] must be extern, Otherwise, bitrev8() can't access it , I will change it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC V4 1/3] add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
On Wed, 2014-10-29 at 13:14 +0800, Wang, Yalin wrote: > this change add CONFIG_HAVE_ARCH_BITREVERSE config option, > so that we can use arm/arm64 rbit instruction to do bitrev operation > by hardware. > We also change byte_rev_table[] to be static, > to make sure no drivers can access it directly. You break the build with this patch. You can't do this until the users of the table are converted. So far, they are not. I submitted patches for these uses, but those patches are not yet applied. Please make sure the dependencies for your patches are explicitly stated. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[RFC V4 1/3] add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
this change add CONFIG_HAVE_ARCH_BITREVERSE config option,
so that we can use arm/arm64 rbit instruction to do bitrev operation
by hardware.
We also change byte_rev_table[] to be static,
to make sure no drivers can access it directly.
Change bitrev16() bitrev32() to be inline function,
don't need export symbol for these tiny functions.
Signed-off-by: Yalin Wang
---
include/linux/bitrev.h | 21 ++---
lib/Kconfig| 9 +
lib/bitrev.c | 19 +++
3 files changed, 30 insertions(+), 19 deletions(-)
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index 7ffe03f..fa2682c 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -3,14 +3,29 @@
#include
-extern u8 const byte_rev_table[256];
+#ifdef CONFIG_HAVE_ARCH_BITREVERSE
+#include
+
+#define bitrev32 __arch_bitrev32
+#define bitrev16 __arch_bitrev16
+#define bitrev8 __arch_bitrev8
+
+#else
static inline u8 bitrev8(u8 byte)
{
return byte_rev_table[byte];
}
-extern u16 bitrev16(u16 in);
-extern u32 bitrev32(u32 in);
+static inline u16 bitrev16(u16 x)
+{
+ return (bitrev8(x & 0xff) << 8) | bitrev8(x >> 8);
+}
+
+static inline u32 bitrev32(u32 x)
+{
+ return (bitrev16(x & 0x) << 16) | bitrev16(x >> 16);
+}
+#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
#endif /* _LINUX_BITREV_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 54cf309..cd177ca 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -13,6 +13,15 @@ config RAID6_PQ
config BITREVERSE
tristate
+config HAVE_ARCH_BITREVERSE
+ boolean
+ default n
+ depends on BITREVERSE
+ help
+ This option provides an config for the architecture which have
instruction
+ can do bitreverse operation, we use the hardware instruction if the
architecture
+ have this capability.
+
config RATIONAL
boolean
diff --git a/lib/bitrev.c b/lib/bitrev.c
index 3956203..ba13610 100644
--- a/lib/bitrev.c
+++ b/lib/bitrev.c
@@ -1,3 +1,4 @@
+#ifndef CONFIG_HAVE_ARCH_BITREVERSE
#include
#include
#include
@@ -6,7 +7,7 @@ MODULE_AUTHOR("Akinobu Mita ");
MODULE_DESCRIPTION("Bit ordering reversal functions");
MODULE_LICENSE("GPL");
-const u8 byte_rev_table[256] = {
+const static u8 byte_rev_table[256] = {
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
@@ -42,18 +43,4 @@ const u8 byte_rev_table[256] = {
};
EXPORT_SYMBOL_GPL(byte_rev_table);
-u16 bitrev16(u16 x)
-{
- return (bitrev8(x & 0xff) << 8) | bitrev8(x >> 8);
-}
-EXPORT_SYMBOL(bitrev16);
-
-/**
- * bitrev32 - reverse the order of bits in a u32 value
- * @x: value to be bit-reversed
- */
-u32 bitrev32(u32 x)
-{
- return (bitrev16(x & 0x) << 16) | bitrev16(x >> 16);
-}
-EXPORT_SYMBOL(bitrev32);
+#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
--
2.1.1
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[RFC V4 1/3] add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
this change add CONFIG_HAVE_ARCH_BITREVERSE config option,
so that we can use arm/arm64 rbit instruction to do bitrev operation
by hardware.
We also change byte_rev_table[] to be static,
to make sure no drivers can access it directly.
Change bitrev16() bitrev32() to be inline function,
don't need export symbol for these tiny functions.
Signed-off-by: Yalin Wang yalin.w...@sonymobile.com
---
include/linux/bitrev.h | 21 ++---
lib/Kconfig| 9 +
lib/bitrev.c | 19 +++
3 files changed, 30 insertions(+), 19 deletions(-)
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index 7ffe03f..fa2682c 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -3,14 +3,29 @@
#include linux/types.h
-extern u8 const byte_rev_table[256];
+#ifdef CONFIG_HAVE_ARCH_BITREVERSE
+#include asm/bitrev.h
+
+#define bitrev32 __arch_bitrev32
+#define bitrev16 __arch_bitrev16
+#define bitrev8 __arch_bitrev8
+
+#else
static inline u8 bitrev8(u8 byte)
{
return byte_rev_table[byte];
}
-extern u16 bitrev16(u16 in);
-extern u32 bitrev32(u32 in);
+static inline u16 bitrev16(u16 x)
+{
+ return (bitrev8(x 0xff) 8) | bitrev8(x 8);
+}
+
+static inline u32 bitrev32(u32 x)
+{
+ return (bitrev16(x 0x) 16) | bitrev16(x 16);
+}
+#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
#endif /* _LINUX_BITREV_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 54cf309..cd177ca 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -13,6 +13,15 @@ config RAID6_PQ
config BITREVERSE
tristate
+config HAVE_ARCH_BITREVERSE
+ boolean
+ default n
+ depends on BITREVERSE
+ help
+ This option provides an config for the architecture which have
instruction
+ can do bitreverse operation, we use the hardware instruction if the
architecture
+ have this capability.
+
config RATIONAL
boolean
diff --git a/lib/bitrev.c b/lib/bitrev.c
index 3956203..ba13610 100644
--- a/lib/bitrev.c
+++ b/lib/bitrev.c
@@ -1,3 +1,4 @@
+#ifndef CONFIG_HAVE_ARCH_BITREVERSE
#include linux/types.h
#include linux/module.h
#include linux/bitrev.h
@@ -6,7 +7,7 @@ MODULE_AUTHOR(Akinobu Mita akinobu.m...@gmail.com);
MODULE_DESCRIPTION(Bit ordering reversal functions);
MODULE_LICENSE(GPL);
-const u8 byte_rev_table[256] = {
+const static u8 byte_rev_table[256] = {
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
@@ -42,18 +43,4 @@ const u8 byte_rev_table[256] = {
};
EXPORT_SYMBOL_GPL(byte_rev_table);
-u16 bitrev16(u16 x)
-{
- return (bitrev8(x 0xff) 8) | bitrev8(x 8);
-}
-EXPORT_SYMBOL(bitrev16);
-
-/**
- * bitrev32 - reverse the order of bits in a u32 value
- * @x: value to be bit-reversed
- */
-u32 bitrev32(u32 x)
-{
- return (bitrev16(x 0x) 16) | bitrev16(x 16);
-}
-EXPORT_SYMBOL(bitrev32);
+#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
--
2.1.1
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Re: [RFC V4 1/3] add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
On Wed, 2014-10-29 at 13:14 +0800, Wang, Yalin wrote: this change add CONFIG_HAVE_ARCH_BITREVERSE config option, so that we can use arm/arm64 rbit instruction to do bitrev operation by hardware. We also change byte_rev_table[] to be static, to make sure no drivers can access it directly. You break the build with this patch. You can't do this until the users of the table are converted. So far, they are not. I submitted patches for these uses, but those patches are not yet applied. Please make sure the dependencies for your patches are explicitly stated. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: [RFC V4 1/3] add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
From: Joe Perches [mailto:j...@perches.com] We also change byte_rev_table[] to be static, to make sure no drivers can access it directly. You break the build with this patch. You can't do this until the users of the table are converted. So far, they are not. I submitted patches for these uses, but those patches are not yet applied. Please make sure the dependencies for your patches are explicitly stated. Oh, byte_rev_table[] must be extern, Otherwise, bitrev8() can't access it , I will change it. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
